Preparation of pi-extended naphthalene diimides and their use as semiconductor

ABSTRACT

The present invention provides the compounds of formulae 
     
       
         
         
             
             
         
       
     
     and electronic devices comprising these compounds.

The present invention relates to core-extended naphthalene diimide derivatives, and to electronic devices comprising the core-extended naphthalene diimide derivatives as semiconducting material.

Naphthalene diimides are a versatile class of chromophores. Naphthalene diimides also gain more and more interest in applications such as in organic field-effect transistors, organic light emitting devices, photovoltaic devices such as dye-sensitized solar cells (DSCs), and xerography.

It is known to modify the properties of naphthalene diimides by functionalization of the parent naphthalene diimide core at the 2, 3, 6 and 7 positions. However, lateral core expansion of naphthalene diimides has only been demonstrated recently.

Suraru, S.-L.; Zhieschang, U.; Klauk, H.; Warthner, F. Chem. Commun. 2011, 47, 11504-11506 describes the following core-extended naphthalene diimide and its use as p-channel semiconductor in thin film transistors:

Hu, Y.; Gao, X.; Di, C.; Yang, X.; Zhang, F.; Liu, Y.; U. H. and Zhu, D. Chem. Mater. 2011, 23, 1204-1215 describes the following core-expanded naphthalene diimides fused with sulfur heterocycles and their use as n-channel semiconductors in thin film transistors:

Doria, F.; Di Antonio, M.; Benotti, M.; Verga, D.; Freccero, M. J. Org. Chem. 2009, 74, 8616-8625 describes the following naphthalene diimide derivatives:

Langhals, H.; Kinzel, S. J. Org. Chem. 2010, 75, 7781-7784 describes naphthalene diimide derivatives:

Zhou, C.; Li, Y.; Zhao, Y.; Zhang, J.; Yang, W.; Li, Y. Org. Lett. 2011, 13, 292-295 describes the following core-substituted naphthalenediimide compound:

Chen, X.; Guo, Y.; Tan, L.; Yang, G.; Li, Y.; Zhang, G.; Liu, Z.; Xu, W.; Zhang, D. J. Mat. Chem. C, 2013, 1, 1087-1092 describes the following compounds and their use as n-channel semiconductors in organic field effect transistors:

It was the object of the present invention to provide core-substituted naphthalene diimide derivatives.

This object is solved by the compounds of claim 1, and the device of claim 5.

The compounds of the present invention are of formulae

wherein

X is O or NR¹³,

-   -   wherein R¹³ is H, C₁₋₃₀-alkyl C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5         to 14 membered heterocyclic system A,         R¹, R², R⁷ and R⁸ are independently from each other H,         C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5 to 14 membered         heterocyclic system A, and         R³, R⁴, R⁵, R⁶, R⁹, R¹⁰, R¹¹ and R¹² are independently from each         other H, C₁₋₃₀-alkyl C₃₋₈-cycloalkyl, C₆₋₁₄-aryl, a 5 to 14         membered heterocyclic system A, halogen, NR¹⁴R¹⁵, OH, OR¹⁶, SH,         SR¹⁷, CN, NO₂, —S—CN, —C(O)—H, —C(O)—R¹⁸, COOH, —C(O)—NR¹⁹R²⁰,         —SO₂—OH, —SO₂—NH₂ or —SO₂—R²¹, wherein     -   R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰ and R²¹ are independently from         each other H, C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5 to         14 membered heterocyclic system A,         or         R³ and R⁴,         R⁵ and R⁶,         R⁹ and R¹⁰, or         R¹¹ and R¹²         together with the C-atoms, to which they are attached, form a         C₅₋₁₄-membered ring system or a 5 to 14 membered heterocyclic         system B,         wherein     -   C₁₋₃₀-alkyl may be substituted with one or more substituents         selected from the group consisting of —O—C₁₋₁₀-alkyl,         —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl,         cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴,     -   C₃₋₈-cycloalkyl may be substituted with one or more substituents         selected from the group consisting of C₁₋₁₀-alkyl,         —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl and         phenyl,     -   C₆₋₁₄-aryl, the C₅₋₁₄-membered ring system, the 5 to 14 membered         heterocyclic system A and the 5 to 14 membered heterocyclic         system B may be substituted with one or more substituents         selected from the group consisting of C₁₋₁₀-alkyl,         —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-cyclopentyl,         cyclohexyl, phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H,         —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴,     -   wherein         -   C₁₋₁₀-alkyl may be substituted with one or more halogen,         -   R²², R²³ and R²⁴ are independently from each other             C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and         -   n is 1 to 15.

C₁₋₁₀-alkyl, C₁₋₃₀-alkyl and C₁₋₂₀-alkyl can be branched or unbranched. Examples of C₁₋₁₀-alkyl are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, n-(1-ethyl)propyl, n-hexyl, n-heptyl, n-octyl, n-(2-ethyl)hexyl, n-nonyl and n-decyl. Examples of C₁₋₂₀-alkyl are C₁₋₁₀-alkyl and n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl and n-icosyl (C₂₀). Examples of C₁₋₃₀-alkyl are C₁₋₂₀-alkyl and n-(2-octyl)dodecyl, n-docosyl (C₂₂), n-tetracosyl (C₂₄), n-(2-decyl)tetradecyl, n-hexacosyl (C₂₆), n-octacosyl (C₂₈) and n-triacontyl (C₃₀).

Examples of C₃₋₈-cycloalkyl are cyclopropyl, cyclobutyl, cyclopentyl, cycloexyl, cycloheptyl and cyclooctyl.

The 5 to 14 membered heterocyclic system A can be a saturated 5 to 14 membered heterocyclic system A or an unsaturated 5 to 14 membered heterocyclic system A including an aromatic 5 to 14 membered heterocyclic system A. The 5 to 14 membered heterocyclic system A includes one or more heteroatoms. The heteroatoms are preferably N, O and/or S. The 5 to 14 membered heterocyclic system A can be monocyclic or polycyclic such as dicyclic.

Examples of 5 to 8 membered saturated heterocyclic systems A are

Examples of unsaturated 5 to 14 membered heterocyclic systems A are

as well as aromatic 5 to 14 membered heterocyclic systems A such as

Examples of C₆₋₁₄-aryl are phenyl and naphthyl.

Examples of halogen are F, Cl, Br and I.

The C₅₋₁₄-membered ring systems can be monocyclic or polycyclic such as dicyclic.

Examples of C₅₋₁₄-membered ring systems are

wherein the C-atoms marked with a star are the C-atoms to which R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² are attached.

The 5 to 14 membered heterocyclic system B can be monocyclic or polycyclic such as dicyclic. The 5 to 14 membered heterocyclic system B includes one or more heteroatoms. The heteroatoms are preferably N, O and/or S. Examples 5 to 14 membered heterocyclic systems B are

wherein the C-atoms marked with a star are the C-atoms to which R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² are attached.

Examples of C₁₋₆-alkylene are methylene, ethylene, propylene and butylene.

In preferred compounds of formulae (1) or (2)

X is O or NR¹³,

-   -   wherein R¹³ is H or C₁₋₃₀-alkyl,         R¹, R², R⁷ and R⁸ are independently from each other H,         C₁₋₃₀-alkyl or C₆₋₁₄-aryl, and         R³ and R⁴,         R⁵ and R⁶,         R⁹ and R¹⁰, or         R¹¹ and R¹²         together with the C-atoms, to which they are attached, form a         C₅₋₁₄-membered ring system or a 5 to 14 membered heterocyclic         system B,         wherein     -   C₁₋₃₀-alkyl may be substituted with one or more substituents         selected from the group consisting of —O—C₁₋₁₀-alkyl,         —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl,         cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴,     -   C₆₋₁₄-aryl, the C₅₋₁₄-membered ring system and the 5 to 14         membered heterocyclic system B may be substituted with one or         more substituents selected from the group consisting of         C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl,         —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl,         phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H, —C(O)O—R²²,         —O—C(O)—R²³ and C(O)—R²⁴,     -   wherein         -   C₁₋₁₀-alkyl may be substituted with one or more halogen,         -   R²², R²³ and R²⁴ are independently from each other             C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and         -   n is 1 to 15.

In more preferred compounds of formulae (1) or (2)

X is O or NR¹³,

-   -   wherein R¹³ is H,         R¹, R², R⁷ and R⁸ are independently from each other C₁₋₂₀-alkyl         or C₆₋₁₄-aryl, and         R³ and R⁴,         R⁵ and R⁶,         R⁹ and R¹⁰, or         R¹¹ and R¹²         together with the C-atoms, to which they are attached, form a         C₅₋₁₄-membered ring system         wherein     -   C₁₋₂₀-alkyl may be substituted with one or more substituents         selected from the group consisting of —O—C₁₋₁₀-alkyl,         —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl,         cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴,     -   C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system may be substituted         with one or more substituents selected from the group consisting         of C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl,         —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl,         phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H, —C(O)O—R²²,         —O—C(O)—R²³ and C(O)—R²⁴,     -   wherein         -   C₁₋₁₀-alkyl may be substituted with one or more halogen,         -   R²², R²³ and R²⁴ are independently from each other             C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and         -   n is 1 to 15.

In most preferred compounds of formulae (1) or (2)

X is O or NR¹³,

-   -   wherein R¹³ is H,         R¹, R², R⁷ and R⁸ are independently from each other C₁₋₂₀-alkyl         or C₆₋₁₄-aryl, and         R³ and R⁴,         R⁵ and R⁶,         R⁹ and R¹⁰, or         R¹¹ and R¹²         together with the C-atoms, to which they are attached, form a         C₅₋₁₄-membered ring system selected from the group consisting of

wherein the C-atoms marked with a star are the C-atoms to which R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² are attached, wherein

-   -   C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system selected from the         group consisting of

-   -   may be substituted with one or more substituents selected from         the group consisting of C₁₋₁₀-alkyl, which may be substituted         with one or more halogen, and halogen.

Particular preferred compounds of formulae (1) are the compounds of formulae

Particular preferred compounds of formulae (2) are the compounds of formulae

The compounds of formulae (1) and (2) can be prepared by methods known in the art.

For example, the compound of formula (1)

wherein

X is O or NR¹³,

-   -   wherein R¹³ is H.         R¹ and R² are independently from each other C₁₋₂₀-alkyl or         C₆₋₁₄-aryl, and         R³ and R⁴, or         R⁵ and R⁶,         together with the C-atoms, to which they are attached, form a         C₅₋₁₄-membered ring system selected from the group consisting of

wherein the C-atoms marked with a star are the C-atoms to which R³ and R⁴, or, R⁵ and R⁶ are attached, wherein

-   -   C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system selected from the         group consisting of

-   -   may be substituted with one or more C₁₋₁₀-alkyl, which may be         substituted with one or more halogen, or with halogen,         may be prepared by         (i) reacting a compound of formula

wherein R¹ and R² are as depicted for formula (1) and Hal is halogen, with

in order to obtain a compound of formula

wherein R¹, R², R³, R⁴, R⁵ and R⁶ are as depicted for formula (1) and Hal is halogen, and (ii) reacting the compound of formula (3) obtained in the first step with a metal catalyst A in order to obtain the compound of formula (1).

The first step of the process or the preparation of a compound of formula (1) is usually performed in a suitable organic solvent such as chloroform. The first step of the process is usually performed at an elevated temperature, for example at a temperature of 40 to 100° C., preferably at a temperature of 50 to 80° C.

The metal catalyst A of the second step of the process for the preparation of a compound of formula (1) is usually a transition metal catalyst. Preferably, it is a Pd-catalyst such as Pd(OAc)₂. The metal catalyst of the second step of the process is usually used in the presence of a base and a suitable solvent. The solvent can be a suitable organic solvent such as DMF. The base can be suitable base such as K₂CO₃. The second step of the process is usually performed at an elevated temperature, for example at a temperature of 50 to 200° C., preferably at a temperature of 80 to 120° C.

The preparation of compounds of formula (4) is described WO 2007/074137, or in X. Gao et al., Org. Lett. 2007, 9, 3917-3920.

For example, a compound of formula (2)

wherein R⁷ and R⁸ are independently from each other C₁₋₂₀-alkyl or C₆₋₁₄-aryl, and R⁹ and R¹⁰, or R¹¹ and R¹² together with the C-atoms, to which they are attached, form a C₅₋₁₄-membered ring system selected from the group consisting of

wherein the C-atoms marked with a star are the C-atoms to which R⁹ and R¹⁰, or, R¹¹ and R¹² are attached, wherein

-   -   C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system selected from the         group consisting of

-   -   may be substituted with one or more C₁₋₁₀-alkyl,         may be prepared by reacting a compound of formula

wherein R⁷ and R⁸ are as depicted for formula (1) and Hal is halogen, with a metal catalyst B and a compound of formula

wherein Hal is halogen in order to obtain a compound of formula (2).

The metal catalyst B of the second step of the process for the preparation of a compound of formula (2) is usually a transition metal catalyst. Preferably, it is a Pd-catalyst such as Pd(OAc)₂, The metal catalyst of the second step of the process is usually used in the presence of a base and a suitable solvent. The solvent can be a suitable organic solvent such as DMF. The base can be suitable base such as K₂CO₃. The second step of the process is usually performed at an elevated temperature, for example at a temperature of 50 to 200° C., preferably at a temperature of 100 to 160° C.

The preparation of compounds of formula (5) is described in Chopin, S.; Chaignon, F. C.; Blart, E.; Odobel, F. J. Mater. Chem. 2007, 17, 4139-4146.

Also part of the invention is an electronic device comprising the compounds of the present invention as semiconducting material.

The electronic device can be any electronic device, for example an organic photovoltaic (OPV) cell, an organic field-effect transistor (OFET) or an organic light emitting diode (OLED). Preferably, the electronic device is an organic field-effect transistor.

Usually, an organic field effect transistor comprises a dielectric layer, a semiconducting layer and a substrate. In addition, an organic field effect transistor usually comprises a gate electrode and source/drain electrodes.

An organic field effect transistor can have various designs, for example bottom-gate design or top-gate design.

The substrate can be any suitable substrate such as undoped or highly doped silicon, for example in form of a silicon waver, or glass, or a plastic substrate such as polyethersulfone, polycarbonate, polysulfone, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

The dielectric layer comprises a dielectric material. The dielectric material can be any suitable material such as aluminium oxide, aluminium oxide in combination with a self-assembled monolayer (SAM) of a phosphonic acid such as C₁₄H₂₉PO(OH)₂ [TDPA] or C₇F₁₅C₁₁H₂₂PO(OH)₂ [FODPA]), silicon dioxide, or an organic polymer such as polystyrene (PS), poly(methyl-methacrylate) (PMMA), poly(4-vinylphenol) (PVP), poly(vinyl alcohol) (PVA), benzocyclobutene (BCB) or polyimide (PI), or a combination of these materials The dielectric layer can have a thickness of 5 to 2000 nm, preferably of 5 to 500 nm, more preferably of 5 to 100 nm.

The semiconducting layer comprises one or more of the compounds of the present invention. The semiconducting layer can have a thickness of 5 to 500 nm, preferably of 10 to 100 nm, more preferably of 20 to 50 nm.

The source/drain electrodes can be made from any suitable source/drain material, for example silver (Ag), gold (Au) or tantalum (Ta). The source/drain electrodes can have a thickness of 1 to 100 nm, preferably from 5 to 50 nm.

The gate electrode can be made from any suitable gate material such as highly doped silicon, aluminium (Al), tungsten (W), indium tin oxide, silver (Ag), gold (Au) or tantalum (Ta), or from a combination of these materials. The gate electrode can have a thickness of 1 to 200 nm, preferably from 5 to 100 nm.

The field effect transistor can be prepared by methods known in the art.

For example, a bottom-gate organic field effect transistor can be prepared as follows:

Aluminium can be deposited on highly doped silicon wafers by thermal evaporation, followed by oxidation of the aluminium layer to aluminium oxide and treatment of the aluminium oxide surface with a phosphonic acid in order to form a self-assembled monolayer (SAM-layer) of the phosphonic acid on the aluminium oxide surface. The semiconducting material can be deposited on the SAM-layer by thermal sublimation. The source and drain electrodes can be formed by evaporating gold through a shadow mask. The back side of the highly doped silicon wafers can be coated with silver ink to serve as the gate electrode.

For example, a bottom-gate organic field effect transistor can be prepared as follows:

Aluminiumoxide can be deposited on highly doped silicon wafers with a thermally grown silicon dioxide layer by atomic layer deposition, followed by treatment of the aluminium oxide surface with a phosphonic acid in order to form a self-assembled monolayer (SAM-layer) of the phosphonic acid on the aluminium oxide surface. The semiconducting material can be deposited on the SAM-layer by thermal sublimation. The source and drain electrodes can be formed by evaporating gold through a shadow mask. The back side of the highly doped silicon wafers can coated be with silver ink to serve as the gate electrode.

Also part of the invention is the use of the compounds of the present invention as semiconducting materials.

The compounds of the present invention show a high stability, in particular towards oxidation, under ambient conditions. Organic devices, in particular organic field effect transistors, comprising compounds of the present invention as semiconducting material show high charge carrier mobilities and high on/off ratios.

EXAMPLES Example 1 Preparation of Compound 1a

Preparation of Compound 4a

Compound 4a is prepared as described in example 9 of WO 2007/074137.

Preparation of Compound 3a

Aniline (1.8 mL) is added to a solution of compound 4a (149 mg, 0.146 mmol) in chloroform (50 mL). The solution is heated under reflux for 40 min. The solvent is removed under reduced pressure, and the remainder is purified by column chromatography (dichloromethane/pentane 1:1). A violet solid is obtained (162 mg, 82%). ¹H NMR (400 MHz, CD₂Cl₂): 11.84 (s, 2H, NH) 7.53-7.47 (m, 2H), 7.37-7.31 (m, 8H), 7.16 (t, ³J=7.6 Hz, 2H), 7.07 (d, ³J=7.6 Hz, 4H), 2.77 (sept, ³J=6.8 Hz, 2H), 2.65 (sept, ³J=6.8 Hz, 2H), 1.18 (d, ³J=6.8 Hz, 12H), 1.11 (d, ³J=6.8 Hz, 12H). ¹³C NMR (100 MHz, CD₂Cl₂): 165.3, 161.7, 151.6, 146.3, 146.1, 141.9, 131.3, 131.0, 130.2, 129.5, 128.5, 125.1, 124.64, 124.56, 122.1, 119.8, 119.0, 108.3, 29.8, 29.6, 24.1, 24.0. MS (MALDI, neg-mode). found: 926.2 [M⁻].

Preparation of Compound 1a

Dry DMF (5 mL) is added to a mixture of compound 3a (76.2 mg, 0.0822 mmol), K₂CO₃ (22.8 mg, 0.165 mmol) und Pd(OAc)₂ (5.4 mg, 26 μmol) under argon. The reaction mixture is stirred at 100° C. for 60 min. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1/1) yielding a dark red solid (20.8 mg, 33%). ¹H NMR (400 MHz, CD₂Cl₂): δ=11.4 (s, 2H), 9.57 (dd, ³J=8.16 Hz, ⁴J=0.76 Hz, 2H), 7.73-7.66 (m, 4H), 7.66-7.57 (m, 2H), 7.49 (d, ³J=7.6 Hz, 2H), 7.46 (d, ³J=7.6 Hz, 2H), 7.41-7.37 (m, 2H), 2.98 (sept, ³J=6.8 Hz, 2H), 2.87 (sept, ³J=6.8 Hz, 2H), 1.22 (d, ³J=6.8 Hz, 12H), 1.20 (d, ³J=6.8 Hz, 12H). ¹³C NMR (100 MHz, CD₂Cl₂): δ=166.0, 164.9, 146.71, 146.66, 144.5, 144.1, 132.0, 131.0, 130.9, 130.20, 130.15, 130.0, 128.8, 125.8, 124.8, 124.6, 122.5, 122.1, 121.6, 118.8, 111.8, 103.3, 29.8, 29.7, 24.2, 24.1. HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₅₀H₄₅N₄O₄ 765.3435. Found 765.3437.

Example 2 Preparation of Compound 2a

DMF (15 mL) is added to a mixture of compound 5a (200 mg, 0.268 mmol), prepared as described in Chopin, S.; Chaignon, F. C.; Blart, E.; Odobel, F. J. Mater. Chem. 2007, 17, 4139-4146, 2-bromophenol (0.08 mL, 0.75 mmol), Pd(OAc)₂ (18.0 mg, 80.6 μmol) and K₂CO₃ (74.0 mg, 0.537 mmol) under argon. The reaction mixture is heated to reflux under argon for 3 hours. The solvent is removed under reduced pressure. The residue is purified by column chromatography (dichloromethane/pentane 2/1). The first fraction obtained is suspended in chloroform, heated to reflux and filtrated after being cooled to room temperature. The so-obtained residue is a light yellow solid (73.0 mg, 35%). ¹H NMR (400 MHz, CD₂Cl₂): δ=9.53 (ddd, ³J=8.3 Hz, ⁴J=1.4 Hz, ⁵J=0.6 Hz, 2H), 7.81 (ddd, ³J=8.5 Hz, ⁴J=1.2 Hz, ⁵J=0.6 Hz, 2H), 7.84-7.79 (m, 2H), 7.61 (t, ³J=7.7 Hz, 2H), 7.56-7.50 (m, 2H), 7.46 (d, ³J=7.7 Hz, 4H), 2.89 (sept, ³J=6.8 Hz, 4H), 1.22 (d, ³J=6.84 Hz, 12H), 1.19 (d, ³J=6.84 Hz, 12H). MS (MALDI, pos-mode): 766.3 [M⁺].

Example 3 Preparation of Compound 1 b

A mixture of compound 1a (53.5 mg, 69.9 μmol), prepared as described in example 1, N-chlorosuccinimide (40.0 mg, 0.300 mmol), chloroform (8 mL) and acetonitrile (10 mL) is heated to reflux. After 3 days additional N-chlorosuccinimide (120 mg, 0.90 mmol) is added to the reaction mixture. After additional 8 hours, the solvent is removed under reduced pressure. The residue is purified by column chromatography and HPLC (dichloromethane/pentane 1:1) to yield compound 1b as a dark red solid (25 mg, 40%). ¹H NMR (400 MHz, CD₂Cl₂) δ=11.55 (s, 2H), 9.55 (dd, ⁴J=1.8 Hz, ⁵J=0.5 Hz, 2H), 7.75 (⁴J=1.8 Hz, 2H), 7.65 (t, ³J=7.5 Hz, 1H), 7.61 (t, ³J=7.5 Hz, 1H), 7.55-7.42 (m, 4H), 2.91 (sept, ³J=6.8 Hz, 2H), 2.84 (sept, ³J=6.8 Hz, 2H), 1.22 (t, ³J=6.8 Hz, 2H), 1.21 (t, ³J=&8 Hz, 2H). HRMS (ESI, positive, acetonitrile/CHCl₃ 1:1): calculated for C₅₀H₄₁Cl₄N₄O₄ 901.1877. Found 901.1881.

Example 4 Preparation of Compound 1c

Preparation of Compound 4b

Compound 4b is prepared as described in X. Gao et al., Org. Lett. 2007, 9, 3917-3920.

Preparation of Compound 3b

Aniline (1.8 mL) is added to a solution of compound 4b (170 mg, 0.211 mmol) in chloroform (50 mL). The solution is heated under reflux for 2 h. The solvent is removed under reduced pressure, and the residue is purified by column chromatography (dichloromethane/pentane 1:1). A violet solid is obtained (153 mg, 87%). ¹H NMR (400 MHz, CD₂Cl₂): 11.88 (s, 2H, NH) 7.40-7.30 (m, 4H), 7.20-7.12 (m, 2H), 7.08-7.00 (m, 4H), 4.19 (t, ³J=7.7 Hz, 2H), 4.12 (t, ³J=7.7 Hz, 2H), 1.79-1.64 (m, 4H), 1.47-1.20 (m, 20H), 0.93-0.80 (m, 6H)

Preparation of Compound 1c

Dry DMF (10 mL) is added to a mixture of compound 3b (153 mg, 0.184 mmol), K₂CO₃ (102 mg, 0.738 mmol) und Pd(OAc)₂ (14 mg, 62 μmol) under argon. The reaction mixture is stirred at 100° C. for 80 min. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1/1) yielding a dark red solid (35 mg, 28%). ¹H NMR (400 MHz, CD₂Cl₂): 11.11 (s, 2H, NH), 9.52 (d, ³J=8.6 Hz, 2H), 7.60-7.52 (m, 2H), 7.41 (d, ³J=7.8 Hz, 2H), 7.39-7.33 (m, 2H), 4.39-4.19 (m, 4H), 1.92-1.77 (m, 4H), 1.48-1.22 (m, 16H), 0.93-0.84 (m, 6H). MS (MALDI, pos-mode): 668.3 [M⁺].

Example 5 Preparation of Compound 1d

Preparation of compound 3c

3-tert-Butylaniline (0.2 mL, 1.26 mmol) is added to a solution of compound 4b (144 mg, 0.179 mmol) in chloroform (10 mL). The solution is heated under reflux for 45 min. The solvent is removed under reduced pressure, and the residue is purified by column chromatography (dichloromethane/pentane 1/1). A violet solid is obtained (129 mg, 76%). ¹H NMR (400 MHz, CDCl₃): 12.09 (s, 2H, NH), 7.25 (dd, ³J=7.8 Hz), 7.18 (ddd, ³J=7.8 Hz, ⁴J=1.6 Hz, ⁴J=1.0 Hz), 7.07 (dd, ⁴J=1.8 Hz), 6.82 (ddd, ³J=7.8 Hz, ⁴J=2.2 Hz, ⁴J=1.0 Hz), 4.20 (t, ³J=7.7 Hz, 2H), 4.15 (t, ³J=7.7 Hz, 2H), 1.79-1.67 (m, 4H), 1.47-1.17 (m, 38H), 0.90-0.82 (m, 6H).

Preparation of Compound 1d

Dry DMF (7 mL) is added to a mixture of compound 3c (99 mg, 0.105 mmol), K₂CO₃ (29 mg, 0.210 mmol) and Pd(OAc)₂ (7.0 mg, 31 μmol) under argon. The reaction mixture is stirred at 100° C. for 60 min. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1/1) yielding a dark red solid. ¹H NMR (400 MHz, CD₂Cl₂): 11.12 (s, 2H, NH), 9.45 (d, ³J=8.7 Hz, 2H), 7.58 (d, ⁴J=1.4 Hz, 2H), 7.49 (dd, ³J=8.7 Hz, ⁴J=1.4 Hz, 2H), 4.13-4.02 (m, 4H), 1.82-1.68 (m, 4H), 1.52 (s, 9H), 1.50-1.24 (m, 18H), 0.93-0.84 (m, 6H).

Example 6 Preparation of Compound 1e

Preparation of Compound 4c

Compound 4c is prepared in analogy to compound 4b as described in example 4.

Preparation of Compound 3d

3-tert-Butylaniline (0.14 mL, 0.88 mmol) is added to a solution of compound 4b (81.1 mg, 0.122 mmol) in chloroform (10 mL). The solution is heated under reflux for 2 h. The solvent is removed under reduced pressure, and the residue is purified by column chromatography (dichloromethane/pentane 4:1). A violet solid is obtained (88 mg, 87%). ¹H NMR (400 MHz, CDCl₃): 12.1 (s, 2H), 7.25 (t, ³J=7.8 Hz, 2H), 7.18 (d, ³J=7.8 Hz, 2H), 7.07 (t, ⁴J=2.0 Hz, 2H), 6.83 (d, ³J=8.0 Hz, 2H), 4.24-4.16 (m, 2H), 4.16-4.08 (m, 2H) (m, 4H), 1.85-1.70 (m, 4H), 1.31 (s, 9H), 1.02 (t, ³J=7.4 Hz, 3H), 1.01 (t, ³J=7.4 Hz, 3H). HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₄₀H₄₃Br₂N₄O₄ 801.1646. Found 806.1650.

Preparation of Compound 1e

Dry DMF (7 mL) is added to a mixture of compound 3d (76.0 mg, 0.095 mmol), K₂CO₃ (26.5 mg, 0.192 mmol) und Pd(OAc)₂ (6.0 mg, 27 μmol) under argon. The reaction mixture is stirred at 100° C. for 90 min. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1/1) yielding a dark red solid (33.0 mg, 54%). ¹H NMR (400 MHz, CD₂Cl₂): 11.11 (s, 2H), 9.44 (d, ³J=8.7 Hz, 2H), 7.59 (d, ⁴J=1.8 Hz, 2H), 7.50 (dd, ³J=8.7 Hz, ⁴J=1.8 Hz, 2H), 4.05-3.98 (m, 4H), 1.82-1.69 (m, 4H), 1.52 (s, 18H), 1.08-0.98 (m, 6H).

Example 7 Preparation of Compound 1f

Preparation of Compound 3e

4-tert-Butylaniline (0.1 mL, 0.63 mmol) is added to a solution of compound 4b (199 mg, 0.247 mmol) in chloroform (30 mL). The solution is heated under reflux for 3 h 15 min. The solvent is removed under reduced pressure, and the residue is purified by column chromatography (dichloromethane/pentane 1:1). A violet solid is obtained (177 mg, 76%). ¹H NMR (400 MHz, CDCl₃) 12.0 (bs, 2H), 7.37-7.30 (m, 4H), 6.99-6.93 (m, 4H), 4.24-4.08 (m, 4H), 1.82-1.62 (m, 4H), 1.33 (s, 9H), 1.45-1.17 (m), 0.92-0.82 (m, 6H). HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₅₀H₆₃Br₂N₄O₄ 941.3211. Found 941.3209.

Preparation of Compound 1f

Dry DMF (8 mL) is added to a mixture of compound 3e (160 mg, 0.170 mmol), K₂CO₃ (48 mg, 0.347 mmol) und Pd(OAc)₂ (11.1 mg, 49.4 μmol) under argon. The reaction mixture is stirred at 100° C. for 60 min. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1/1) yielding a dark red solid (42.8 mg, 32%). ¹H NMR (400 MHz, CD₂Cl₂): 11.25 (s. 2H), 9.78 (d, ⁴J=2.0 Hz, 2H), 7.74 (dd, ³J=8.4 Hz, ⁴J=2.0 Hz, 2H), dd (³J=8.4 Hz, ⁵J=0.5 Hz, 2H), 4.43 (t, ³J=7.5 Hz, 2H), 4.30 (t, ³J=7.5 Hz, 2H), 2.00-1.88 (m, 2H), 1.88-1.76 (m, 2H), 1.55 (s, 9H), 1.52-1.22 (m, 20H), 0.92-0.85 (m, 6H). HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₅₀H₆₃Br₂N₄O₄ 941.3211. Found 941.3209.

Example 8 Preparation of Compound 1g

Preparation of Compound 3f

3-Bis(trifluoromethyl)aniline (0.20 mL, 1.2 mmol) is added to a solution of compound 4b (72.3 mg, 0.0898 mmol) in toluene (5 mL). After heating the solution at 70° C. for 4 days 0.1 mL 0.6 mmol) 3-bis(trifluoromethyl)aniline is added. The solution is heated at 70° C. for 2 days more. The solvent is removed under reduced pressure, and the residue is purified by column chromatography (dichloromethane/pentane 1:4). A red solid is obtained (80.6 mg, 81%). ¹H NMR (400 MHz, CDCl₃): 12.00 (s, 2H), 7.63 (s, 2H), 7.38 (s, 4H), 4.26-4.17 (m, 4H), 1.82-1.68 (m, 4H), 1.47-1.19 (m, 20H), 0.92-0.81 (m, 6H). HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₄₆H₄₃Br₂F₁₂N₄O₄ 1101.1454. Found 1101.1457.

Preparation of Compound 1g

Dry DMF (5 mL) is added to a mixture of compound 3f (83.8 mg, 0.076 mmol), K₂CO₃ (21.5 mg, 0.156 mmol) und Pd(OAc)₂ (5.2 mg, 23 μmol) under argon. The reaction mixture is stirred at 100° C. for 45 min, and then refluxed for 1 h. After cooling of the reaction mixture to room temperature, the solvent is removed under vacuo. The residue is purified by column chromatography (dichloromethane/pentane 1:1) yielding a dark red solid (22.8 mg, 32%). ¹H NMR (400 MHz, CDCl₃): 11.3 (s, 2H), 8.03 (s, 2H), 7.92 (s, 2H), 4.36-4.25 (m, 2H), 4.21 (t, ³J=7.4 Hz, 2H), 2.01 (tt, ³J=6.8 Hz, 2H), 1.77 (tt, ³J=6.8 Hz, 2H), 1.62-1.18 (m, 20H), 0.93-0.83 (m, 6H). HRMS (ESI, acetonitrile/CHCl₃ 1:1, pos-mode): calcd for C₄₆H₄₁F₁₂N₄O₄ 941.2931. Found 941.2929.

Example 9 Preparation of Compound 2b

Preparation of Compound 5b

The compound 5b is prepared in analogy to 5a.

Preparation of Compound 2b

DMF (7 mL) is added to a mixture of compound 5b (180 mg, 0.278 mmol), 2-bromophenol (0.08 mL, 0.75 mmol), Pd(OAc)₂ (18.7 mg, 83.3 μmol) and K₂CO₃ (76.3 mg, 0.537 mmol) under argon. The reaction mixture is heated to reflux under argon for 3 hours. The solvent is removed under reduced pressure. The residue is purified by column chromatography (dichloromethane). A yellow fluorescent solid is obtained (30.1 mg, 16%). ¹H NMR (400 MHz, CDCl₃): 9.61 (d, ³J=8.0 Hz, 2H), 7.84 (d, ³J=7.9 Hz, 2H), 7.76-7.72 (m, 2H), 7.56-7.50 (m, 2H), 4.35 (t, ³J=7.8 Hz, 4H), 1.89-1.81 (m, 2H), 1.52-1.08 (m), 0.82 (t, ³J=6.8 Hz, 6H).

Example 10 Method for Determining the Transistor Characteristics

Highly doped p-type silicon (100) wafers (0.01-0.02 Ω·cm) were used as substrates A. Highly doped p-type silicon (100) wafers (0.005-0.02 Ω·cm) with a 100 nm thick thermally grown SiO₂ layer (capacitance 34 nF/cm²) were used as substrates B.

Onto substrates A, a 30 nm thick layer of aluminum is deposited by thermal evaporation in a Leybold UNIVEX 300 vacuum evaporator from a tungsten wire, at a pressure of 2×10⁻⁶ mbar and with an evaporation rate of 1 nm/s. The surface of the aluminum layer is oxidized by a brief exposure to an oxygen plasma in an Oxford reactive ion etcher (RIE, oxygen flow rate: 30 sccm, pressure: 10 mTorr, plasma power: 200 W, plasma duration 30 sec) and the substrate is then immersed into a 2-propanol solution of a phosphonic acid (1 mMol solution of C₁₄H₂₉PO(OH)₂ [TDPA] or 1 mMol solution of C₇F₁₅C₁₁H₂₂PO(OH)₂ [FODPA]) and left in the solution for 1 hour, which results in the formation of a self-assembled monolayer (SAM) of phosphonic acid molecules on the aluminum oxide surface. The substrate is taken out of the solution and rinsed with pure 2-propanol, dried in a stream of nitrogen and left for 10 min on a hotplate at a temperature of 100° C. The total capacitance of the AlO_(x)/SAM gate dielectric on substrate A is 810 nF/cm² in case of C₁₄H₂₉PO(OH)₂ and 710 nF/cm² in case of C₇F₁₅C₁₁H₂₂PO(OH)₂.

On substrates B, an about 8 nm thick layer of Al₂O₃ is deposited by atomic layer deposition in a Cambridge NanoTech Savannah (80 cycles at a substrate temperature of 250° C.). The surface of the aluminum oxide layer is activated by a brief exposure to an oxygen plasma in an Oxford reactive ion etcher (RIE, oxygen flow rate: 30 sccm, pressure: 10 mTorr, plasma power: 200 W, plasma duration 30 sec) and the substrate is then immersed into a 2-propanol solution of a phosphonic acid (1 mMol solution of C₁₄H₂₉PO(OH)₂ [TDPA] or 1 mMol solution of C₇F₁₅C₁₁H₂₂PO(OH)₂ [FODPA]) and left in the solution for 1 hour, which results in the formation of a self-assembled monolayer (SAM) of phosphonic acid molecules on the aluminum oxide surface. The substrate is taken out of the solution and rinsed with pure 2-propanol, dried in a stream of nitrogen and left for 10 min on a hotplate at a temperature of 100° C. The total capacitance of the SiO₂/AlO_(x)/SAM gate dielectric on substrate B is 32 nF/cm² (independent on the choice of the phosphonic acid).

The contact angle of water on the TDPA-treated substrates is 108°, and on the FODPA-treated substrates 118°.

A 30 nm thick film of compounds of the present invention as organic semiconductor is deposited by thermal sublimation in a Leybold UNIVEX 300 vacuum evaporator from a molybdenum boat, at a pressure of 2×10⁻⁶ mbar and with an evaporation rate of 0.3 nm/s.

For the source and drain contacts 30 nm of gold is evaporated through a shadow mask in a Leybold UNIVEX 300 vacuum evaporator from tungsten boat, at a pressure of 2×10⁻⁶ mbar and with an evaporation rate of 0.3 nm/s. The transistors have a channel length (L) ranging from 10 to 100 μm and a channel width (W) ranging from 50 to 1000 μm.

To be able to contact the back side of the silicon wafer, the wafer (which also serves as the gate electrode of the transistors) is scratched on the back side and coated with silver ink.

The electrical characteristics of the transistors are measured on a Micromanipulator 6200 probe station using an Agilent 4156C semiconductor parameter analyzer. All measurements are performed in air at room temperature. The probe needles are brought into contact with the source and drain contacts of the transistors by putting them down carefully on top of the gold contacts. The gate electrode is contacted through the metal substrate holder onto which the wafer is placed during the measurements.

To obtain the transfer curve the drain-source voltage (V_(DS)) is held to 3 V (in case of substrate A) or 40 V (in case of substrate B). The gate-source voltage V_(GS) is swept at medium speed from 0 to 3 V in steps of 0.03 V (substrate A) or from 0 to 40 V in steps of 0.4 V (substrate B) and back. The charge-carrier mobility is extracted in the saturation regime from the slope of (I_(D))^(1/2) versus V_(GS).

To obtain the output characteristics the drain-source voltage (V_(DS)) is swept at medium speed from 0 to 3 V in steps of 0.03 V (substrate A) and from 0 to 40 V in steps of 0.4 V (substrate B), while the gate-source voltage V_(GS) is held at up to 8 different voltages (e.g. 0, 0.5, 1, 1.5, 2, 2.5, 3 V in case of substrate A or 0, 10, 20, 30, 40 V in case of substrate B).

The results are depicted in Table 1.

TABLE 1 Organic Substrate Hole Electron Semi- Temper- Mobility Mobility On/Off con- Sub- ature μ_(p) μ_(e) Ratio ductor strate SAM T_(sub) [° C.] [cm²/Vs] [cm²/Vs] I_(on)/I_(off) 1a B FODPA 100 0.2 0.006  7 × 10⁵/ 10⁴ 1a A FODPA 100 0.02 0.003  5 × 10⁵/ 3 × 10² 1a A TDPA 100 0.003 2 × 10⁴ 1b B FODPA 100 0.0001 2 × 10⁴ 1b B TDPA 100 0.0001 10⁴ 1b A FODPA 100 0.0001 10² 1b A TDPA 100 0.0003 3 × 10³ 1c B FODPA 100 0.007 2 × 10⁴ 1d B TDPA 100 0.0019 10⁴ 1d A TDPA 100 0.0029 3 × 10³ 1e B FODPA 100 0.03 10⁴ 1e B TDPA 100 0.002 10⁵ 1f B FODPA 100 0.07 10⁵ 1f B TDPA 100 0.00064 10³ 1f A FODPA 100 0.02 2 × 10⁵ 1g B FODPA 100 0.0008 3 × 10² 1g B TDPA 100 0.0002 3 × 10² 2a B FODPA 100 0.0038 10⁴ 2a B TDPA 100 0.06 10⁷ 2a A FODPA 100 0.0012 5 × 10² 2a A TDPA 100 0.03 5 × 10⁵ 2b B FODPA 100 0.006 0.02  2 × 10³/ 10⁴ 2b B TDPA 100 0.006 10⁵ 

1.-7. (canceled)
 8. A compound of the formula (1) or (2)

wherein X is O or NR¹³, wherein R¹³ is H, C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5 to 14 membered heterocyclic system A, R¹, R², R⁷ and R⁸ are independently from each other H, C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5 to 14 membered heterocyclic system A, and R³, R⁴, R⁵, R⁶, R⁹, R¹⁰, R¹¹ and R¹² are independently from each other H, C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl, a 5 to 14 membered heterocyclic system A, halogen, NR¹⁴R¹⁵, OH, OR¹⁶, SH, SR¹⁷, CN, NO₂, —S—CN, —C(O)—H, —C(O)—R¹⁸, COOH, —C(O)—NR¹⁹R²⁰, —SO₂—OH, —SO₂—NH₂ or —SO₂—R²¹, wherein R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰ and R²¹ are independently from each other H, C₁₋₃₀-alkyl, C₃₋₈-cycloalkyl, C₆₋₁₄-aryl or a 5 to 14 membered heterocyclic system A, or R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² together with the C-atoms, to which they are attached, form a C₅₋₁₄-membered ring system or a 5 to 14 membered heterocyclic system B, wherein C₁₋₃₀-alkyl is optionally substituted with one or more substituents selected from the group consisting of —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl, cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, C₃₋₈-cycloalkyl is optionally substituted with one or more substituents selected from the group consisting of C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl and phenyl, C₆₋₁₄-aryl, the C₅₋₁₄-membered ring system, the 5 to 14 membered heterocyclic system A and the 5 to 14 membered heterocyclic system B is optionally substituted with one or more substituents selected from the group consisting of C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl, phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, wherein C₁₋₁₀-alkyl is optionally substituted with one or more halogen, R²², R²³ and R²⁴ are independently from each other C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and n is 1 to
 15. 9. The compound of claim 8, wherein X is O or NR¹³, wherein R¹³ is H or C₁₋₃₀-alkyl, R¹, R², R⁷ and R⁸ are independently from each other H, C₁₋₃₀-alkyl or C₆₋₁₄-aryl, and R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² together with the C-atoms, to which they are attached, form a C₅₋₁₄-membered ring system or a 5 to 14 membered heterocyclic system B, wherein C₁₋₃₀-alkyl is optionally substituted with one or more substituents selected from the group consisting of —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl, cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, C₆₋₁₄-aryl, the C₅₋₁₄-membered ring system and the 5 to 14 membered heterocyclic system B is optionally substituted with one or more substituents selected from the group consisting of C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl, phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, wherein C₁₋₁₀-alkyl is optionally substituted with one or more halogen, R²², R²³ and R²⁴ are independently from each other C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and n is 1 to
 15. 10. The compound of claim 8, wherein X is O or NR¹³, wherein R¹³ is H, R¹, R², R⁷ and R⁸ are independently from each other C₁₋₂₀-alkyl or C₆₋₁₄-aryl, and R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² together with the C-atoms, to which they are attached, form a C₅₋₁₄-membered ring system wherein C₁₋₂₀-alkyl is optionally substituted with one or more substituents selected from the group consisting of —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, phenyl, cyclopentyl, cyclohexyl, halogen, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system is optionally substituted with one or more substituents selected from the group consisting of C₁₋₁₀-alkyl, —O—C₁₋₁₀-alkyl, —[—O—C₁₋₆-alkylene-]_(n)-O—C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl, phenyl, halogen, CN, NO₂, —S—CN, —C(O)—H, —C(O)O—R²², —O—C(O)—R²³ and C(O)—R²⁴, wherein C₁₋₁₀-alkyl is optionally substituted with one or more halogen, R²², R²³ and R²⁴ are independently from each other C₁₋₁₀-alkyl, cyclopentyl, cyclohexyl or phenyl, and n is 1 to
 15. 11. The compound of claim 8, wherein X is O or NR¹³, wherein R¹³ is H, R¹, R², R⁷ and R⁸ are independently from each other C₁₋₂₀-alkyl or C₆₋₁₄-aryl, and R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² together with the C-atoms, to which they are attached, form a C₅₋₁₄-membered ring system selected from the group consisting of

wherein the C-atoms marked with a star are the C-atoms to which R³ and R⁴, R⁵ and R⁶, R⁹ and R¹⁰, or R¹¹ and R¹² are attached, wherein C₆₋₁₄-aryl and the C₅₋₁₄-membered ring system selected from the group consisting of

is optionally substituted with one or more substituents selected from the group consisting of C₁₋₁₀-alkyl, which is optionally substituted with one or more halogen, and halogen.
 12. An electronic device comprising the compounds of claim
 8. 13. The electronic device of claim 12, wherein the electronic device is an organic field effect transistor.
 14. A semiconducting material comprising the compound as claimed in claim
 8. 